Process for increasing the yield in civetone, starting from civet



Patented July 16, 1929.

UNITED STATES PATENT OFFICE.

LEOIOLD EUZICKA, OF UTRECI-IT, NETHERLANDS, ASSIGNOR TO THE FIRM M. NAEF & 00., OF GENEVA, SWITZERLAND, COMPOSED (3F MARTIN NAEF AND FREDERIC FIRMENICH, BOTH OF GENEVA,-SWITZERLAND.

PROCESS FOR INCREASING THE YIELD IN CIVETONE, STAR-TING FROM CIVET.

No Drawing. Application filed January 25, 1927, Serial No. 163,567, and in Switzerland March 17, 1926.

It is known from the work of Erwin Sack (D. R. P. 279,313 and Chemikcr Zeitung vol. 39, page 538) that the material of civet which has a musklike odor is a ketone, C H O, called civetone. It has now been found that there also exists in civet an alcohol, namely, civetol, C H O in a greater proportionthan civetone, but the odor of which is of no practical interest as a perfume.

Now, it has been found that this alcohol can easily be transformed by oxidation or dehydrogenation into civetone. which makes it possible to obtain from civet av quantity of civetone more than twice as large as that hitherto obtained by the simple extraction of civetone.

The subject of the present invention is therefore a process for increasing the yield in civetone, starting from civet.

This process is characterized by the transformation into civetone of the civetol contained in civet.

In carrying out the process it is possible, for example, first of all to extract the civetone from the neutral civet oil by the Erwin Sack process or by another method. The parts of the neutral civet oil which do not react with the ketone reagents are then fractionated by distillation and the fraction which possesses approximately the same boiling point as that of civetone (about 170 C. under a pressure of 1 mm.) forms a mass melting towards 58 C. and is practically pure civetol.

The civetol may be purified in the known manner by transforming it into phthalic ester. The properties of civetol are not, however, greatly altered by this purification and the latter is consequently not absolutely necessary for the subsequent transformation of the civetol into ketone.

The transformation of the civetol into ketone may be carried out by the general methods of changing alcohols into ketones, such as oxidation by CllIOHllC acid, catalytic oxidation by oxygen in the presence of silver or even catalytic dehydrogenation by the passage of the alcohol at a high temperature over nickel, copper or platinum.

The civetone which is thus obtained is identical with that extracted directly from the civet. It gives a semi-carbazone melting at 187 C. from which it is possible to recover, by heating with acids, civetone having a meltin; point of 32 C.

For carrying out the oxidation or dehydro- E sample 1.

Civet in an alcohol solution is boiled with a quantity of an alkali metal hydroxide greater than the theoretical quantity necessary for the saponification and neutralization of the fatty esters and fatty acids it contains. The soluble alkali metal salts of the fatty acids are transformed by the addition of a concentrated aqueous solution of calcium chloride in ex cess into calcium salts which are not easily soluble and which are precipitated and separated by filtering.

The precipitate is well washed with alcohol and then the latter is driven off by distillation. The residue obtained is extracted by ether or benzene and the oil dissolved distilled in a vacuum. the fractions passing over between 160 C. and 180 C. (under 1 mm. pressure) being retained for subsequent use. The crude civet may be treated with steam before saponification, in order to remove therefrom the components having an unpleasant smell.

The above mentioned fractions of the neutral civet oil are treated with a view to the separation from them of the civetone with a semicarbazide solution in the usual manner, in order to form the civetone semicarbazone. The civetol contained in this oil can then be separated quantitatively from the semicarbazone formed, by simple digestion with petroleum ether, the latter being a good solvent of the civetol only.

The civetol thus obtained after distillation of the petroleum ether, is oxidized either by the theoretical quantity of chromic acid in an acetic solution, or by an aqueous solution of potassium bichromate and sulphuric acid, with a slight application of heat.

The civetone resulting may be Withdrawn from the product of oxidation by transform-- ing itinto its carbazone.

The civetol which may not have been oxidized can be separated afresh With petroleum ether and then subjected to oxidation again.

E mample After having analyzed for the quantities of ketone and alcohol contained in a sample of the neutral civet oil obtained according to Example 1, this neutral oil may then be 0xi dized directly, the necessary quantity of chromic acid for transforming the civetol into civetone being employed.

E wample 3.

Ewample 4.

The pure civetol obtained according to Example 1 is dehydrogenated by passing it over platinum heated to about 250 (1., preferably under a vacuum.

The civetol obtained according to Example 1 is oxidized by passing it in the presence of oxygen and under a pressure reduced to 25 mm. over silver heated to about 300 C.

lVhat I claim is:

1. The process of increasing the quantity of civetone obtainable from neutral civet oil Which comprises oxidizing the civetol contained in said oil to civetone.

2. The process of increasing the quantity of civetone obtainable from eivet which comprises the steps of preparing a neutral oil from said civet. said oil containing both civetone and civetol and oxidizing the latter to civetone.

3. The process of increasing the quantity of civetone obtainable from neutral civet oil, which comprises passing the civet oil over a dehydrogenation catalyst heated to about 250 to 300 degrees centigrade.

4. The process of increasing the quantity of civetone obtainable from neutral civet oil, which comprises passing the civet oil under a reduced pressure over copper heated to ap proximately 250 degrees centigrade.

In testimony whereof I aflix my signature.

LEOPOLD RUZIOKA. 

